High surface area pentasil zeolite and process for making same

ABSTRACT

A family of crystalline aluminosilicate zeolites has been synthesized that is a layered pentasil zeolite. These zeolites are represented by the empirical formula: 
       M m   n+ R r   p+ Al 1-x E x Si y O z    
     where M is an alkali, alkaline earth, or rare earth metal such as sodium or strontium, R can be a mixture of organoammonium cations and E is a framework element such as gallium, iron, boron, or indium. These zeolites are characterized by unique x-ray diffraction patterns and compositions and have catalytic properties for carrying out various hydrocarbon conversion processes.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation-in-Part of copending applicationcopending application Ser. No. 15/996,330 which is aContinuation-In-Part of Ser. No. 14/636,898 filed Mar. 3, 2015.

FIELD OF THE INVENTION

The present invention relates to a new family of aluminosilicatezeolites. This family of zeolites are pentasil zeolites similar to MFItype zeolites and is characterized by unique x-ray diffraction patternsand compositions and have catalytic properties for carrying out varioushydrocarbon conversion processes.

BACKGROUND

Zeolites are crystalline aluminosilicate compositions which aremicroporous and which are formed from corner sharing AlO₂ and SiO₂tetrahedra. Numerous zeolites, both naturally occurring andsynthetically prepared, are used in various industrial processes.Synthetic zeolites are prepared via hydrothermal synthesis employingsuitable sources of Si, Al and structure directing agents such as alkalimetals, alkaline earth metals, amines, or organoammonium cations. Thestructure directing agents reside in the pores of the zeolite and arelargely responsible for the particular structure that is ultimatelyformed. These species balance the framework charge associated withaluminum and can also serve as space fillers. Zeolites are characterizedby having pore openings of uniform dimensions, having a significant ionexchange capacity, and being capable of reversibly desorbing an adsorbedphase which is dispersed throughout the internal voids of the crystalwithout significantly displacing any atoms which make up the permanentzeolite crystal structure. Zeolites can be used as catalysts forhydrocarbon conversion reactions, which can take place on outsidesurfaces as well as on internal surfaces within the pore.

One particular zeolitic material, classified as ZSM-5, is disclosed inBeck, et al., U.S. Pat. No. 6,180,550, issued on Jan. 30, 2001. Thezeolite comprises a synthetic porous crystalline material having acomposition involving the molar relationship

X₂O₃:(n)YO₂,

wherein X is a trivalent element, such as aluminum, boron, iron and/orgallium, preferably aluminum; Y is a tetravalent element such as siliconand/or germanium, preferably silicon; and n is less than 25, and whereinthe slope of the nitrogen sorption isotherm of the material at a partialpressure of nitrogen of 0.4 to 0.7 and a temperature of 77° K is greaterthan 30.

While there are many types of zeolites, new zeolites provide forimproved reaction conditions in the conversion of lower valuehydrocarbon streams to higher value hydrocarbon products.

SUMMARY

The present invention comprises a pentasil-layered zeolite having amicroporous crystalline structure comprising a framework of AlO₂ andSiO₂ tetrahedral units, and an empirical composition in the assynthesized and anhydrous basis expressed by the empirical formula ofM_(m) ^(n+)R_(r) ^(p+)AlSi_(y)O_(z) where M is at least one exchangeablecation selected from the group consisting of alkali and alkaline earthmetals, “m” is the mole ratio of M to Al and varies from 0 to 3, R is atleast one organo cation selected from the group consisting of quaternaryammonium cations, diquaternary ammonium cations, quaternary phosphoniumcations, and methonium cations, “r” is the mole ratio of R to Al and hasa value of about 0.1 to about 30, “n” is the weight average valence of Mand has a value of about 1 to about 2, “p” is the weighted averagevalence of R and has a value of about 1 to about 2, “y” is the moleratio of Si to Al and varies from greater than 32 to about 200 and “z”is the mole ratio of O to Al and has a value determined by the equationz=(m·n+r·p+3+4·y)/2. The zeolite of claim 1 further characterized by thex-ray diffraction pattern having at least the d spacing and intensitiesset forth in the following Table A:

TABLE A 2Θ d(Å) I/Io 7.92-7.99 11.04-11.31 m 8.79-8.88  9.94-11.09 m20.28-20.56 4.31-4.35 w 23.10-23.18 3.83-3.84 vs 23.86-24.05 3.69-3.72 m29.90-30.05 2.97-2.98 w 45.02-45.17 2.00-2.01 w

The zeolite of claim 1 wherein the zeolite has a microporous crystallinestructure comprising a framework of AlO₂ and SiO₂ tetrahedral units,further including the element E and having the empirical composition inthe as synthesized and anhydrous basis expressed by the empiricalformula of M_(m) ^(n+)R_(r) ^(p+)Al_(1-x)E_(x)Si_(y)O_(z) where “m” isthe mole ratio of M to (Al+E) and varies from 0 to 3, “r” is the moleratio of R to (Al+E) and has a value between 0.1 and 30, E is an elementselected from the group consisting of gallium, iron, boron, indium andmixtures thereof, “x” is the mole fraction of E and has a value from 0to 1.0, “y” is the mole ratio of Si to (Al+E) and varies from greaterthan 32 to 200 and “z” is the mole ratio of O to (Al+E) and has a valuedetermined by the equation z=(m·n+r·p+3+4·y)/2. The zeolite of claim 1wherein the zeolite has a mesopore surface area between 140 m²/g and 400m²/g. The zeolite of claim 1 wherein M is selected from the groupconsisting of lithium, sodium, potassium, and mixtures thereof. Thezeolite of claim 1 wherein M is a mixture of an alkali metal and analkaline earth metal. The zeolite of claim 1 wherein R is selected fromthe group consisting of tetrabutylammonium hydroxide,tetrabutylphosphonium hydroxide, hexamethonium dihydroxide and mixturesthereof. The zeolite of claim 1 wherein R is a halide or hydroxidecompound of an organoammonium cation. The zeolite of claim 1 wherein Ris a mixture of tetrabutylammonium cation and a quaternary ammoniumcation. The zeolite of claim 1 wherein the silica/alumina (Si/Al₂) ratiois between 64 and 400.

An embodiment of the invention is a process for the production of apentasil-layered zeolite catalyst, comprising forming a reaction mixturecomprising reactive compounds M, R, Al and Si; and reacting the mixtureat reaction conditions, wherein the reaction conditions include atemperature between 80° C. and 150° C., and a reaction time between 10hours and 5 days, to form a microporous crystalline structure comprisinga framework of AlO₂ and SiO₂ tetrahedral units, and an empiricalcomposition in the as synthesized and anhydrous basis expressed by theempirical formula of M_(m) ^(n+)R_(r) ^(p+)AlSi_(y)O_(z); wherein thereactive compounds include M, a cation selected from the groupconsisting of alkali and alkaline earth metals; R, an organoammoniumcation selected from the group consisting of quaternary ammoniumcations, diquaternary ammonium cations; and wherein “m” is the moleratio of M to Al and varies from 0 to 3, “r” is the mole ratio of R toAl and has a value of between 0.1 and 30, “n” is the weight averagevalence of M and has a value of 1 to 2, “p” is the weighted averagevalence of R and has a value of 1 to 2, “y” is the mole ratio of Si toAl and varies from greater than 32 to 200 and “z” is the mole ratio of Oto Al and has a value determined by the equation z=(m·n+r·p+3+4·y)/2. Anembodiment of the invention is one, any or all of prior embodiments inthis paragraph up through this embodiment in this paragraph furthercomprising the addition of reactive source E, wherein E is an elementselected from the group consisting of gallium, iron, boron, indium andmixtures thereof, to form a microporous crystalline structure comprisinga framework of AlO₂ and SiO₂ tetrahedral units, and an empiricalcomposition in the as synthesized and anhydrous basis expressed by theempirical formula of M_(m) ^(n+)R_(r) ^(p+)Al_(1-x)E_(x)Si_(y)O_(z);wherein m″ is the mole ratio of M to (Al+E) and varies from 0 to 1, “r”is the mole ratio of R to (Al+E) and has a value between 0.1 and 30, “n”is the weight average valence of M and has a value of 1 to 2, “p” is theweighted average valence of R and has a value of 1 to 2, “x” is the molefraction of E and has a value from 0 to 1.0, “y” is the mole ratio of Sito (Al+E) and varies from greater than 32 to 200 and “z” is the moleratio of O to (Al+E) and has a value determined by the equationz=(m·n+r·p+3+4·y)/2. An embodiment of the invention is one, any or allof prior embodiments in this paragraph up through this embodiment inthis paragraph where R is selected from the group consisting oftetrabutylammonium hydroxide, tetrabutylphosphonium hydroxide andmixtures thereof. An embodiment of the invention is one, any or all ofprior embodiments in this paragraph up through this embodiment in thisparagraph wherein R is a halide or hydroxide compound of anorganoammonium cation. An embodiment of the invention is one, any or allof prior embodiments in this paragraph up through this embodiment inthis paragraph where R is a mixture of tetrabutylammonium hydroxide anda quaternary ammonium cation. An embodiment of the invention is one, anyor all of prior embodiments in this paragraph up through this embodimentin this paragraph where M is selected from the group consisting ofsodium, potassium, and mixtures thereof. An embodiment of the inventionis one, any or all of prior embodiments in this paragraph up throughthis embodiment in this paragraph where the reaction mixture is reactedat a temperature between 100° C. and 125° C. An embodiment of theinvention is one, any or all of prior embodiments in this paragraph upthrough this embodiment in this paragraph where the reaction mixture isreacted at a temperature between 110° C. and 150° C.

Another, or second embodiment of the process of making the zeolite, is aprocess for the production of a pentasil MFI/MEL-layered zeolitecatalyst having a 2-D structure, comprising forming a reaction mixturecontaining reactive sources of M, R, Al, and Si; and reacting thereaction mixture at reaction conditions of 80° C. to 150° C. for aperiod of time of between 10 hours and 5 days the reaction mixturehaving the a composition expressed in terms of mole ratios of the oxidesof aM_(2/n)ObR_(1 2/n)OcR_(2 2/n)Al₂O₃eSiO₂hH₂O; wherein the reactivecompounds include M, a cation selected from the group consisting ofalkali, alkaline earth metals and mixtures thereof; R, an organoammoniumcation selected from the group consisting of quaternary ammoniumcations, diquaternary ammonium cations and mixtures thereof; Al in theform of Al₂O₃; and Si in the form of SiO₂; and wherein “a” has a valueof 0.1 to 3, “b” has a value of 1 to 30, “c” has a value of 0 to 1, “e”has a value of 64 to 400 and “h” has a value of 50 to 1000. Anembodiment of the invention is one, any or all of prior embodiments inthis paragraph up through the second embodiment in this paragraphfurther comprising forming the reaction mixture with reactive source E,wherein E is an element selected from the group consisting of gallium,iron, boron, indium and mixtures thereof; and reacting the reactionmixture at reaction conditions of 85° C. to 225° C. for a period of timeof 1 day to 15 days the reaction mixture having the a compositionexpressed in terms of mole ratios of the oxides ofaM_(2/n)ObR_(1 2/n)OcR_(2 2/n)1-dAl₂O₃dE₂O₃eSiO₂hH₂O; wherein “a” has avalue of 0.1 to 3, “b” has a value of 1 to 30, “c” has a value of 0 to1, “d” has a value of 0 to 1, “e” has a value of 64 to 400 and “h” has avalue of 50 to 1000.

Other objects, advantages and applications of the present invention willbecome apparent to those skilled in the art from the following detaileddescription.

DETAILED DESCRIPTION

A new family of zeolitic materials has been successfully prepared. Thetopology of this zeolite is unique as determined by its x-raydiffraction spectrum. The structure is related to MFI/MEL class ofzeolite framework types.

There are many allotropes for zeolites having similar chemical formulae.The different allotropes can have very different physical and chemicalproperties, and can lead to many different uses. The easiest example isto look at the allotropes of carbon, a single type of atom but with manydifferent structures, that leads to materials having, in some cases,diametrically opposed properties. Likewise for the allotropes of manyzeolites, the discovery of new allotropes can be unexpected and theirproperties can also be unexpected and subsequently can lead to new usesfrom those properties.

For industrial catalytic application there is a need for zeolite of highexternal surface areas. Applicants have successfully prepared this newfamily of pentasil zeolites similar to MFI/MEL type zeolites. Thematerials are prepared via the use of a single commercially availablestructure directing agent, such as tetrabutylammonium hydroxide, usingthe Charge Density Mismatch Approach to zeolite synthesis (U.S. Pat. No.7,578,993). The organoammonium compounds used to make this pentasilzeolite are non-cyclic or contain cyclic substituents and are generallyquite simple. Examples of organoammonium compounds used to make thispentasil zeolite include tetrabutylammonium (TBA) andtetrabutylphosphonium (TBP) cation

The present invention is a new pentasil layer zeolite and forms a porousstructure that has a mesopore surface area between 140 m²/g and 400m²/g. The zeolite has a microporous crystalline structure comprising aframework of AlO₂ and SiO₂ tetrahedral units, and an empiricalcomposition in the as synthesized and anhydrous basis expressed by theempirical formula of:

M_(m) ^(n+)R_(r) ^(p+)AlSi_(y)O_(z).

In the formula, M is at least one exchangeable cation selected from thegroup consisting of alkali and alkaline earth metals, “m” is the moleratio of M to Al and varies from about 0 to about 3, R is at least oneorgano cation selected from the group consisting of quaternary ammoniumcations, diquaternary ammonium cations, quaternary phosphonium cations,and methonium cations, “r” is the mole ratio of R to Al and has a valueof about 0.1 to about 30, “n” is the weight average valence of M and hasa value of about 1 to about 2, “p” is the weighted average valence of Rand has a value of about 1 to about 2, “y” is the mole ratio of Si to Aland varies from greater than 32 to about 200 and “z” is the mole ratioof 0 to Al and has a value determined by the equation:

z=(m·n+r·p+3+4·y)/2.

The zeolite is further characterized in that it has the x-raydiffraction pattern having at least the d spacing and intensities setforth in Table A:

TABLE A 2Θ d(Å) I/Io 7.92-7.99 11.04-11.31 m 8.79-8.88  9.94-11.09 m20.28-20.56 4.31-4.35 w 23.10-23.18 3.83-3.84 vs 23.86-24.05 3.69-3.72 m29.90-30.05 2.97-2.98 w 45.02-45.17 2.00-2.01 w

The zeolite can be seen as characterized by the very strong peak in thex-ray diffraction pattern at 2θ from 23.10-23.18.

In one embodiment, the zeolite can be formed with a metal E. The zeoliteforms a microporous crystalline structure and has the empiricalcomposition in the as synthesized and anhydrous basis expressed by theempirical formula of:

M_(m) ^(n+)R_(r) ^(p+)Al_(1-x)E_(x)Si_(y)O_(z)

where “m” is the mole ratio of M to (Al+E) and varies from 0 to 3, “r”is the mole ratio of R to (Al+E) and has a value of about 0.1 to about30, E is an element selected from the group consisting of gallium, iron,boron, indium and mixtures thereof, “x” is the mole fraction of E andhas a value from 0 to 1.0, “y” is the mole ratio of Si to (Al+E) andvaries from greater than 32 to about 200 and “z” is the mole ratio of Oto (Al+E) and has a value determined by the equation:

z=(m·n+r·p+3+4·y)/2.

The metal M can be a mixture of alkali metals and alkaline earth metals,with a preferred metal or metal combination comprising one or more oflithium, sodium and potassium. The organo cation can comprise anorganoammonium ion such as tetrabutylammonium cation, or anorganophosphonium ion such as tetrabutylphosphonium cation, or amethonium ion such as hexamethonium cation. These can be selected forthe reaction mixture to form the zeolite from tetrabutylammoniumhydroxide, tetrabutylphosphonium hydroxide, and hexamethoniumdihydroxide. The R can be selected from a mixture of quaternaryorganoammonium cations. The R can be a halide or a hydroxide of theorganoammonium cation. A preferred R comprises a mixture oftetrabutylammonium cation and a quaternary ammonium cation.

The pentasil zeolite formed will have a silica to alumina ratio (Si/Al₂)ratio is between 32 and 400.

The pentasil-zeolite is formed by creating a reaction mixture comprisingreactive compounds having M, R, Al and Si. The reaction mixture isreacted under reaction conditions that include a temperature between 80°C. and 150° C., and a reaction time between 10 hours and 5 days. Thisforms a microporous crystalline structure comprising a framework of AlO₂and SiO₂ tetrahedral units, and an empirical composition in the assynthesized and anhydrous basis expressed by the empirical formula of:

M_(m) ^(n+)R_(r) ^(p+)AlSi_(y)O_(z)

The process can further include adding the additional reactive source E,wherein E is an element selected from one or more of the metals:gallium, iron, boron and indium to form the structure with the empiricalcomposition in the as synthesized and anhydrous basis expressed by theempirical formula of:

M_(m) ^(n+)R_(r) ^(p+)Al_(1-x)E_(x)Si_(y)O_(z).

The reaction temperature is preferred to be between 100° C. and 125° C.,or with a preferred reaction temperature between 110° C. and 150° C.

In one embodiment, the process to produce the zeolite includes forming areaction mixture with the reactive sources of M, R, Al, and Si. Themixture is reaction at a temperature between 80° C. to 150° C. for aperiod of time of between 10 hours and 5 days and the reaction mixturehas a composition expressed in terms of mole ratios of the oxides of:

aM_(2/n)O:bR_(1 2/n)O:cR_(2 2/n):Al₂O₃ :eSiO₂ :hH₂O.

The reactive sources include M, a cation selected from alkali oralkaline earth elements; R an organoammonium cation; Al in the form ofAl₂O₃; and Si in the form of SiO₂. In the mixture, the value of “a” isbetween 0.1 and 3, the value of “b” is between 1 and 30, the value of“c” is between 0 and 1, the value of “e” is between 64 and 400, and thevalue of “h” is between 50 and 1000.

The process can further include adding the additional reactive speciesE, wherein E is one or more elements from gallium, iron, boron andindium. The reaction conditions include a temperature between 85° C. and225° C. for a period from 1 day to 15 days. The reaction mixture has acomposition expressed in terms of mole ratios of the oxides of:

aM_(2/n)O:bR_(1 2/n)O:cR_(2 2/n):1-dAl₂O₃ :dE₂O₃ :eSiO₂ :hH₂O;

wherein “a” has a value of 0.1 to 3, “b” has a value of 1 to 30, “c” hasa value of 0 to 1, “d” has a value of 0 to 1, “e” has a value of 64 to400 and “h” has a value of 50 to 1000.

The structure of the zeolite of this invention was determined by x-rayanalysis.

The x-ray patterns presented in the following examples were obtainedusing standard x-ray powder diffraction techniques. The radiation sourcewas a high-intensity, x-ray tube operated at 45 kV and 35 ma. Thediffraction pattern from the copper K-alpha radiation was obtained byappropriate computer-based techniques. Flat compressed powder sampleswere continuously scanned at 2° to 70° (2θ). Interplanar spacings (d) inAngstrom units were obtained from the position of the diffraction peaksexpressed as θ where θ is the Bragg angle as observed from digitizeddata. Intensities were determined from the integrated area ofdiffraction peaks after subtracting background, “I_(o)” being theintensity of the strongest line or peak, and “I” being the intensity ofeach of the other peaks. For high throughput samples, diffractionpatterns were collected on the Bruker-AXS GADDS diffractometer equippedwith an area detector, which covered 2Θ=3−38°.

As will be understood by those skilled in the art the determination ofthe parameter 2θ is subject to both human and mechanical error, which incombination can impose an uncertainty of about ±0.4° on each reportedvalue of 2θ. This uncertainty is, of course, also manifested in thereported values of the d-spacings, which are calculated from the 2θvalues. This imprecision is general throughout the art and is notsufficient to preclude the differentiation of the present crystallinematerials from each other and from the compositions of the prior art. Insome of the x-ray patterns reported, the relative intensities of thed-spacings are indicated by the notations vs, s, m, and w whichrepresent very strong, strong, medium, and weak, respectively. In termsof 100×II/I_(o), the above designations are defined as:w=0-15; m=15-60:s=60-80 and vs=80-100.

1n certain instances, the purity of a synthesized product may beassessed with reference to its x-ray powder diffraction pattern. Thus,for example, if a sample is stated to be pure, it is intended only thatthe x-ray pattern of the sample is free of lines attributable tocrystalline impurities, not that there are no amorphous materialspresent.

Example 1

An aluminosilicate reaction solution was prepared by first mixing 13.15g of aluminum tri-sec-butoxide (95⁺%), 777.62 g tetrabutylammoniumhydroxide (55 mass-% solution), and 700 g of ice water mixture whilestirring vigorously. After thorough mixing, 1167.98 g tetraethylorthosilicate was added. The reaction mixture was homogenized for anadditional hour with a high-speed mechanical stirrer. A compositeaqueous solution containing 2.75 g of NaOH dissolved in 137.7 gdistilled water was added, drop-wise, to the aluminosilicate solution.After the addition was completed, the resulting reaction mixture washomogenized for 1 hour, transferred to a 2000 ml Parr stainless steelautoclave which was heated to 115° C. and maintained at that temperaturefor 59 hrs. The solid product was recovered by centrifugation, washedwith de-ionized water, and dried at 80° C.

The product was identified as a pentasil zeolite by powder x-raydiffraction. Representative diffraction lines observed for the productare shown in Table 1. The product composition was determined byelemental analysis to consist of the following mole ratios: Si/Al=59.8,Na/Al=0.82. A portion of the material was calcined by ramping to 560° C.for 5 hours followed by an 8-hour dwell in air. The BET surface area was697 m²/g, the micropore area was 474 m²/g, the mesopore area was 223m²/g, the micropore volume was 0.253 cc/g, and mesopore volume was 0.953cc/g. Scanning Electron Microscopy (SEM) revealed clusters of nanospheres of less than 20 nm. Chemical analysis was as follows: 0.74% Al,46.0% Si, and 0.52% Na, Na/Al=0.82, Si/Al₂=119.

TABLE 1 2θ d(Å) I/I₀% 7.92 11.15 m 8.8 10.04 m 20.38 4.35 w 23.13 3.84vs 23.98 3.7 m 29.96 2.98 w 45.14 2 w

Example 2

An aluminosilicate reaction solution was prepared by first mixing 13.87g of aluminum tri-sec-butoxide (95⁺%), 386.39 g tetrabutylammoniumhydroxide (55 mass-% solution), and 300 g of ice water mixture whilestirring vigorously. After thorough mixing, 580.35 g tetraethylorthosilicate was added. The reaction mixture was homogenized for anadditional hour with a high-speed mechanical stirrer. A compositeaqueous solution containing 2.73 g of NaOH dissolved in 116.67 gdistilled water was added, drop-wise, to the aluminosilicate solution.After the addition was completed, the resulting reaction mixture washomogenized for 1 hour, transferred to a 2000 ml Parr stainless steelautoclave which was heated to 115° C. and maintained at that temperaturefor 57 hrs. The solid product was recovered by centrifugation, washedwith de-ionized water, and dried at 80° C.

The product was identified as a pentasil zeolite by powder x-raydiffraction. Representative diffraction lines observed for the productare shown in Table 2. The product composition was determined byelemental analysis to consist of the following mole ratios: Si/Al=24.9,Na/Al=0.92. A portion of the material was calcined by ramping to 560° C.for 5 hours followed by a 8 hour dwell in air. The BET surface area was517 m²/g, the micropore area was 258 m²/g, the mesopore area was 259m²/g, the micropore volume was 0.135 cc/g, and mesopore volume was 0.94cc/g. Scanning Electron Microscopy (SEM) revealed clusters of nanospheres of less than 20 nm. Chemical analysis was as follows: 1.73% Al,44.9% Si, and 1.37% Na, Na/Al=0.93, Si/Al₂=49.8.

TABLE 2 2θ d(Å) I/I₀% 7.94 11.12 m 8.79 10.04 m 20.38 4.35 w 23.16 3.83vs 23.86 3.72 m 29.96 2.98 w 45.07 2.00 w

Example 3

An aluminosilicate reaction solution was prepared by first mixing 13.73g of aluminum tri-sec-butoxide (95⁺%), 559.89 g tetrabutylphosphoniumhydroxide (40 mass-% solution), and 200 g of ice water mixture whilestirring vigorously. After thorough mixing, 574.76 g tetraethylorthosilicate was added. The reaction mixture was homogenized for anadditional hour with a high-speed mechanical stirrer. A compositeaqueous solution containing 2.70 g of NaOH dissolved in 48.92 gdistilled water, was added, drop-wise, to the aluminosilicate solution.After the addition was completed, the resulting reaction mixture washomogenized for 1 hour, transferred to a 2000 ml Parr stainless steelautoclave which was heated to 115° C. and maintained at that temperaturefor 120 hrs. The solid product was recovered by centrifugation, washedwith de-ionized water, and dried at 80° C.

The product was identified as a pentasil zeolite by powder x-raydiffraction. Representative diffraction lines observed for the productare shown in Table 3. The product composition was determined byelemental analysis to consist of the following mole ratios: Si/Al=33.78,Na/Al=0.67. A portion of the material was calcined by ramping to 560° C.for 5 hours followed by an 8-hour dwell in air. The BET surface area was526 m²/g, the micropore area was 220 m²/g, the mesopore area was 306m²/g, the micropore volume was 0.115 cc/g, and mesopore volume was 0.99cc/g. Scanning Electron Microscopy (SEM) revealed clusters of nanospheres of less than 20 nm. Chemical analysis was as follows: 1.22% Al,42.8% Si, and 0.70% Na, Na/Al=0.67, Si/Al₂=67.5.

TABLE 3 2θ d(Å) I/I₀% 7.99 11.04 m 8.88 9.94 m 20.50 4.32 w 23.16 3.83vs 24.05 3.69 m 30.05 2.97 w 45.02 2.01 w

Example 4

An aluminosilicate reaction solution was prepared by first mixing 2.17 gof aluminum tri-sec-butoxide (95⁺%), 362.46 g tetrabutylammoniumhydroxide (55 mass-% solution), and 300 g of water ice while stirringvigorously. After thorough mixing, 544.42 g tetraethyl orthosilicate wasadded. The reaction mixture was homogenized for an additional hour witha high-speed mechanical stirrer. A composite aqueous solution containing0.85 g of NaOH dissolved in 90.10 g distilled water was added,drop-wise, to the aluminosilicate solution. After the addition wascompleted, the resulting reaction mixture was homogenized for 1 hour,transferred to a 2000 ml Parr stainless steel autoclave which was heatedto 115° C. and maintained at that temperature for 48 hrs. The solidproduct was recovered by centrifugation, washed with de-ionized water,and dried at 80° C.

The product was identified as a pentasil zeolite by powder x-raydiffraction. Representative diffraction lines observed for the productare shown in Table 4. The product composition was determined byelemental analysis to consist of the following mole ratios: Si/Al=202,Na/A1=1.33. A portion of the material was calcined by ramping to 560° C.for 5 hours followed by an 8-hour dwell in air. The BET surface area was567 m²/g, the micropore area was 206 m²/g, the mesopore area was 361m²/g, the micropore volume was 0.11 cc/g, and mesopore volume was 0.92cc/g. Scanning Electron Microscopy (SEM) revealed clusters of nanospheres of less than 20 nm. Chemical analysis was as follows: 0.22% Al,46.2% Si, and 0.22% Na, Na/Al=1.33, Si/Al₂=404.

TABLE 4 2θ d(Å) I/I₀% 7.98 11.07 m 8.88 9.94 m 23.20 3.83 vs 24.06 3.69m 29.9 2.98 w 45.22 2.00 w

While the invention has been described with what are presentlyconsidered the preferred embodiments, it is to be understood that theinvention is not limited to the disclosed embodiments, but it isintended to cover various modifications and equivalent arrangementsincluded within the scope of the appended claims.

What is claimed is:
 1. A pentasil-layered zeolite having a microporouscrystalline structure comprising a framework of AlO₂ and SiO₂tetrahedral units, and an empirical composition in the as synthesizedand anhydrous basis expressed by the empirical formula of:M_(m) ^(n+)R_(r) ^(p+)AlSi_(y)O_(z) where M is at least one exchangeablecation selected from the group consisting of alkali and alkaline earthmetals, “m” is the mole ratio of M to Al and varies from 0 to 3, R is atleast one organo cation selected from the group consisting of quaternaryammonium cations, diquaternary ammonium cations, quaternary phosphoniumcations, and methonium cations, “r” is the mole ratio of R to Al and hasa value of about 0.1 to about 30, “n” is the weight average valence of Mand has a value of about 1 to about 2, “p” is the weighted averagevalence of R and has a value of about 1 to about 2, “y” is the moleratio of Si to Al and varies from greater than 32 to about 200 and “z”is the mole ratio of O to Al and has a value determined by the equation:z=(m·n+r·p+3+4·y)/2.
 2. The zeolite of claim 1 further characterized bythe x-ray diffraction pattern having at least the d spacing andintensities set forth in the following Table A: TABLE A 2Θ d(Å) I/Io7.92-7.99 11.04-11.31 m 8.79-8.88  9.94-11.09 m 20.28-20.56 4.31-4.35 w23.10-23.18 3.83-3.84 vs 23.86-24.05 3.69-3.72 m 29.90-30.05 2.97-2.98 w45.02-45.17 2.00-2.01 w


3. The zeolite of claim 1 wherein the zeolite has a mesopore surfacearea between 140 m²/g and 400 m²/g.
 4. The zeolite of claim 1 wherein Mis selected from the group consisting of lithium, sodium, potassium, andmixtures thereof.
 5. The zeolite of claim 1 wherein M is a mixture of analkali metal and an alkaline earth metal.
 6. The zeolite of claim 1wherein R is selected from the group consisting of where R is selectedfrom the group consisting of tetrabutylammonium hydroxide,tetrabutylphosphonium hydroxide, hexamethonium dihydroxide and mixturesthereof.
 7. The zeolite of claim 1 wherein R is a halide or hydroxidecompound of an organoammonium cation.
 8. The zeolite of claim 1 whereinR is a mixture of tetrabutylammonium cation and a quaternary ammoniumcation.
 9. The zeolite of claim 1 wherein the silica/alumina (Si/Al₂)ratio is between 32 and
 400. 10. A process for the production of apentasil-layered zeolite catalyst, comprising: forming a reactionmixture comprising reactive compounds M, R, Al and Si; and reacting themixture at reaction conditions, wherein the reaction conditions includea temperature between 80° C. and 150° C., and a reaction time between 10hours and 5 days, to form a microporous crystalline structure comprisinga framework of AlO₂ and SiO₂ tetrahedral units, and an empiricalcomposition in the as synthesized and anhydrous basis expressed by theempirical formula of:M_(m) ^(n+)R_(r) ^(p+)AlSi_(y)O_(z); wherein the reactive compoundsinclude M, a cation selected from the group consisting of alkali andalkaline earth metals; R, an organoammonium cation selected from thegroup consisting of quaternary ammonium cations, diquaternary ammoniumcations; and wherein “m” is the mole ratio of M to Al and varies from 0to 3, “r” is the mole ratio of R to Al and has a value of between 0.1and 30, “n” is the weight average valence of M and has a value of 1 to2, “p” is the weighted average valence of R and has a value of 1 to 2,“y” is the mole ratio of Si to Al and varies from greater than 32 to 200and “z” is the mole ratio of O to Al and has a value determined by theequation:z=(m·n+r·p+3+4·y)/2.
 11. The process of claim 10 where R is selectedfrom the group consisting of tetrabutylammonium hydroxide,tetrabutylphosphonium hydroxide, hexamethonium dihydroxide and mixturesthereof.
 12. The process of claim 10 wherein R is a halide or hydroxidecompound of an organoammonium cation.
 13. The process of claim 10 whereR is a mixture of tetrabutylammonium hydroxide and a quaternary ammoniumcation.
 14. The process of claim 10 where M is selected from the groupconsisting of sodium, potassium, and mixtures thereof.
 15. The processof claim 10 where the reaction mixture is reacted at a temperaturebetween 100° C. and 125° C.
 16. The process of claim 10 where thereaction mixture is reacted at a temperature between 110° C. and 150° C.17. A process for the production of an MFI-layered zeolite catalysthaving a 2-D structure, comprising: forming a reaction mixturecontaining reactive sources of M, R, Al, and Si; and reacting thereaction mixture at reaction conditions of 80° C. to 150° C. for aperiod of time of between 10 hours and 5 days the reaction mixturehaving the a composition expressed in terms of mole ratios of the oxidesof:aM_(2/n)O:bR_(12/n)O:cR_(22/n):Al₂O₃ :eSiO₂ :hH₂O; wherein the reactivecompounds include M, a cation selected from the group consisting ofalkali, alkaline earth metals and mixtures thereof; R, an organoammoniumcation selected from the group consisting of quaternary ammoniumcations, diquaternary ammonium cations and mixtures thereof; Al in theform of Al₂O₃; and Si in the form of SiO₂; and wherein “a” has a valueof 0.1 to 3, “b” has a value of 1 to 30, “c” has a value of 0 to 1, “e”has a value of 64 to 400 and “h” has a value of 50 to 1000.